[commit: ghc] master: Only use TBAA when LLVM > 2.8. (#5782) (8783718)

[David Terei]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/878371810de61632d58962608fb3db588d9c2fbd

>---------------------------------------------------------------

commit 878371810de61632d58962608fb3db588d9c2fbd
Author: David Terei <davidterei at gmail.com>
Date:   Tue Jan 17 00:23:22 2012 -0800

    Only use TBAA when LLVM > 2.8. (#5782)

>---------------------------------------------------------------

 compiler/llvmGen/LlvmCodeGen.hs |    5 ++++-
 compiler/main/DriverPipeline.hs |   10 ++++++++--
 compiler/main/DynFlags.hs       |   21 +++++++++++++--------
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/compiler/llvmGen/LlvmCodeGen.hs b/compiler/llvmGen/LlvmCodeGen.hs
index 00f4292..531d90a 100644
--- a/compiler/llvmGen/LlvmCodeGen.hs
+++ b/compiler/llvmGen/LlvmCodeGen.hs
@@ -27,6 +27,7 @@ import UniqSupply
 import Util
 import SysTools ( figureLlvmVersion )
 
+import Data.IORef ( writeIORef )
 import Data.Maybe ( fromMaybe )
 import System.IO
 
@@ -47,10 +48,12 @@ llvmCodeGen dflags h us cmms
             in (d,env')
     in do
         showPass dflags "LlVM CodeGen"
-        bufh <- newBufHandle h
         dumpIfSet_dyn dflags Opt_D_dump_llvm "LLVM Code" $ docToSDoc pprLlvmHeader
+        bufh <- newBufHandle h
         Prt.bufLeftRender bufh $ pprLlvmHeader
         ver  <- (fromMaybe defaultLlvmVersion) `fmap` figureLlvmVersion dflags
+        -- cache llvm version for later use
+        writeIORef (llvmVersion dflags) ver
         env' <- {-# SCC "llvm_datas_gen" #-}
                 cmmDataLlvmGens dflags bufh (setLlvmVer ver env) cdata []
         {-# SCC "llvm_procs_gen" #-}
diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index f1c0417..df6e7fd 100644
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -1306,6 +1306,8 @@ runPhase SplitAs _input_fn dflags
 
 runPhase LlvmOpt input_fn dflags
   = do
+    ver <- io $ readIORef (llvmVersion dflags)
+
     let lo_opts  = getOpts dflags opt_lo
         opt_lvl  = max 0 (min 2 $ optLevel dflags)
         -- don't specify anything if user has specified commands. We do this
@@ -1315,7 +1317,8 @@ runPhase LlvmOpt input_fn dflags
         optFlag  = if null lo_opts
                        then [SysTools.Option (llvmOpts !! opt_lvl)]
                        else []
-        tbaa | dopt Opt_LlvmTBAA dflags = "--enable-tbaa=true"
+        tbaa | ver < 29                 = "" -- no tbaa in 2.8 and earlier
+             | dopt Opt_LlvmTBAA dflags = "--enable-tbaa=true"
              | otherwise                = "--enable-tbaa=false"
 
 
@@ -1340,12 +1343,15 @@ runPhase LlvmOpt input_fn dflags
 
 runPhase LlvmLlc input_fn dflags
   = do
+    ver <- io $ readIORef (llvmVersion dflags)
+
     let lc_opts = getOpts dflags opt_lc
         opt_lvl = max 0 (min 2 $ optLevel dflags)
         rmodel | opt_PIC        = "pic"
                | not opt_Static = "dynamic-no-pic"
                | otherwise      = "static"
-        tbaa | dopt Opt_LlvmTBAA dflags = "--enable-tbaa=true"
+        tbaa | ver < 29                 = "" -- no tbaa in 2.8 and earlier
+             | dopt Opt_LlvmTBAA dflags = "--enable-tbaa=true"
              | otherwise                = "--enable-tbaa=false"
 
     -- hidden debugging flag '-dno-llvm-mangler' to skip mangling
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index a443989..bcd43e3 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -588,7 +588,9 @@ data DynFlags = DynFlags {
   haddockOptions        :: Maybe String,
 
   -- | what kind of {-# SCC #-} to add automatically
-  profAuto              :: ProfAuto
+  profAuto              :: ProfAuto,
+
+  llvmVersion           :: IORef (Int)
  }
 
 class HasDynFlags m where
@@ -824,13 +826,15 @@ initDynFlags dflags = do
  refFilesToClean <- newIORef []
  refDirsToClean <- newIORef Map.empty
  refGeneratedDumps <- newIORef Set.empty
+ refLlvmVersion <- newIORef 28
  return dflags{
-        ways            = ways,
-        buildTag        = mkBuildTag (filter (not . wayRTSOnly) ways),
-        rtsBuildTag     = mkBuildTag ways,
-        filesToClean    = refFilesToClean,
-        dirsToClean     = refDirsToClean,
-        generatedDumps   = refGeneratedDumps
+        ways           = ways,
+        buildTag       = mkBuildTag (filter (not . wayRTSOnly) ways),
+        rtsBuildTag    = mkBuildTag ways,
+        filesToClean   = refFilesToClean,
+        dirsToClean    = refDirsToClean,
+        generatedDumps = refGeneratedDumps,
+        llvmVersion    = refLlvmVersion
         }
 
 -- | The normal 'DynFlags'. Note that they is not suitable for use in this form
@@ -922,7 +926,8 @@ defaultDynFlags mySettings =
         extensions = [],
         extensionFlags = flattenExtensionFlags Nothing [],
         log_action = defaultLogAction,
-        profAuto = NoProfAuto
+        profAuto = NoProfAuto,
+        llvmVersion = panic "defaultDynFlags: No llvmVersion"
       }
 
 type LogAction = Severity -> SrcSpan -> PprStyle -> MsgDoc -> IO ()